Dryer damper and control mechanism

ABSTRACT

A dryer and damper control mechanism designed to dry articles by forced warm air including a plurality of internal baffles directing the flow of heated air through the dryer, a first set of dampers co-operating to guide the air downwardly through the articles being dried, a second pair of dampers to direct the heated air upwardly through the articles being dried and, controls to precisely regulate the temperature, humidity, and volume of the heated air through all portions of the apparatus.

United States Patent Parkes [54] DRYER DAMPER AND CONTROL MECHANISM [72]Inventor: Ralph C. Parkes, North Hancock St.

& Lehigh Ave., Rydal, Pa. 19133 22 Filed: Sept. 24, 1970 21 Appl.No.:74,958

Kellman ..34/l9l X 1s 1 3,705,461 451 Dec. 12,1972

2,249,624 7/1941 Bichowsky ..34/77 ux Primary ExaminerFrederick L.Matteson Assistant Examiner-Harry B. Ramey Attorney-Louis Necho [57]ABSTRACT A dryer and damper control mechanism designed to dry articlesby forced warm air including a plurality of internal baffles directingthe flow of heated air through the dryer, a first set of dampersco-operating to guide the air downwardly through the articles beingdried, a second pair of dampers to direct the heated air upwardlythrough the articles being dried and, controls to precisely regulate thetemperature, humidity, and volume of the heated air through all portionsof the apparatus.

5 Claims, 3 Drawing Figures SHEET 1 BF 2 INVENTOR V RALPH C.- ARKESBfwmr ATTORNEY.

PATENTED nu: 12 I972 SHEET 2 [IF 2 ATTORNEY.

- 1 DRYER DAMPER AND CONTROL MECHANISM BACKGROUND OF THE INVENTION Thisinvention relates generally to-the art of material drying and, moreparticularly, is directed to a dryer apparatus including specificcontrols to accurately regulate the direction, temperature and volume offlow of heated air through the apparatus.

Prior workers in this field have developed various types of dryingapparatus employing both oil and gas air heaters which function to heatair within the dryer for introduction to a drying chamber by means offan type air handling units. In most prior art devices, the air handlingunits included a fanhaving specific output characteristics and,accordingly, the prior art devices could not satisfactorily and easilyvary the volume of air introduced to the drying chamber during thedrying cycle. Additionally, the prior art dryers of which I am familiar,operate at temperatures directly related to the temperatures developedat'the air heater, andcontrols and apparatus havefn'otto date beendeveloped to precisely regulate the temperature of the heated airflowing through the drying chamber. Some prior workers have attemptedto'develop methods to regulate temperature, volume and direction of flowof heated air through the drying chamber, but all prior art controlsystems have tended to be complicated," expensive and relativelyunreliable in use, due to the complexity of the apparatus.

Due to such variables as bed depth, moisture content of the articlesbeing dried, porosity or permeability to air flow, the ability of theproduct to withstand drying from one side without degrading by surfacecarbonization or caramelization, it is the usual practice in presentlyavailable apron conveyor type dryers to reverse and/or modify thetemperature and volume of air flow by prefixed zones or increments ofdryer length. This present method necessitates preliminary testing whichis customarily accomplished in a small laboratory unit. Such sampletesting may introduce inaccuracies in that the product tested on a smallscale may not be representative of the commercial product whenconsidering operating conditions such as time, temperature, direction,and air flow characteristics.

When providing directional flow through a dryer, it is I the presentpractice to fabricate dryers with up-through or down-through air flow byproviding a plurality of fans arranged for operation throughpredetermined fixed directional zones. Drying conditions havecustomarily been controlled as a function of the dryer length, therebycreating operating difficulties when it is desired to vary internalconditions.

SUMMARY OF THE INVENTION ment in terms of both timeand efiiciency ofoperation and results.

The dryer damper and control mechanism of the present inventionincorporates an air generating system which employs air by-pass dampersto control the volume of air passing through I 'the. product anddirectional dampers including pre-programming means to regulate air floweither up-through or down-through the drying bed regardless of fanlocation or zone position with relation to the bed. The directionaldampers permit pre-programmed controlled air intake and exhaust relativeto total air intake and exhaust. A plurality of co-operating dampersposition within the dryer construction to permit time, volume, directionand temperature adjustments to the air flow through the bed to bereadily made on an automatically variable basis. I

The mechanism includes means for automatically reversing the directionof air flow to match the diffu sion 'rate of a product to therebypermit-higher temperature and diffusion rates. The reversing air flowavoids carbonization or caramelization to thus both increase the dryingrate and improve the quality of the final product.

It is a purpose of this invention to increase the versatilityof thistype of dryer by providing automatic timing, temperature and volumepressure control mechanism that may be re-programmed' by zones toalternately reverse air flow and/0r re-set the same to correspond withcommercial product drying requirements and to increase capacity. This isaccomplished by a series of dampers which automatically or manuallyrespond to a re-evaluated or automatically sensed program for drying;accomplished from a pulsation through reversal of air flow at timedintervals per zone to a static or conventional pattern. This system hasproved valuable in maintaining an evaporation cooling effect withproducts such as starch or onions where cooking occurs with highertemperatures caused by a continuous directional air flow pattern to thuseliminate former problems resulting in pinking or slumping of onions andthe modification of starch.

It is. therefore an object of the present invention to provide animproved dryer damper and control mechanism of the type set forth.

It is another object of the present invention to provide a novel dryerdamper control mechanism including interior baffle construction andmeans to control the flow of heated air through the baffle arrangement.

It is another object of the present invention to provide a novel dryerdamper and control mechanism incorporating precise air volume controlapparatus designed to quickly and efficiently adjust air quantities.

It is a further object of the present invention to provide a novel dryerdamper and control mechanism including a plurality of interior bafflesand co-operating dampers to direct heated air flow about the baffleconstruction, including recirculation, direction, application andexhaust.

It is another object of the present invention to provide a drying systemthat can automatically be programmed to direct air flow up-through ordownthrough the product being dried for predetermined varying periods oftime without regard to zoning, by utilizing a plurality of dampers andprecise damper positioning mechanisms.

It is another object of the present invention to provide damper controlmeans to regulate air flow through a dryer, including means to controlair volume for multiple selective periods as predetermined andprogrammed, including balancing inlet and exhaust air volumes.

It is another object of the present invention to provide apparatuscapable of programming pulsating drying techniques incorporatingalternating air flow directional changes at short time intervals andincluding temperature control mechanisms.

Another object of the present invention is to provide a novel dryerdamper and control mechanism incorporating readily adjustable means toregulate air temperature and humidity conditions within the dryingchamber.

It is another object of the present invention to provide a novel dryerdamper and control mechanism that is rugged in construction, simple indesign, and troublefree when in use. A

Other objects and a fuller understanding of the invention will be had byreferring to the following description and claims of a preferredembodiment thereof, taken in conjunction with the accompanying drawings,wherein like reference characters refer to similar parts throughout theseveral views.

IN THE DRAWINGS FIG. 1 is a perspective view of a dryer constructed inaccordance with the present invention and partially broken away toexpose interior construction details.

FIG. 2 is a side elevational view of the invention of FIG. 1 with theside casing removed to expose interior construction, and showing thearrangement of drying chamber dampers in the first operating postion.

FIG. 3 is a view similar to FIG. 2 and showing the arrangement of dryingchamber dampers in the second operating position.

DESCRIPTION OF THE PREFERRED EMBODIMENT OF THE INVENTION Althoughspecific terms are used in the following description for the sake ofclarity, these terms are intended to refer only to the particularstructure of my invention selected for illustration in the drawings, andare not intended to define or limit the scope of the invention.

Referring now to the drawings, 1 show a dryer generally comprising astructural steel frame 12 and a substantially air-tight casing 14 whichmay be fabricated of sheet steel or other sturdy construction and boltedor otherwise affixed to the frame 12, in wellknown manner. A gear motorcontrol operator 18 mounts upon the roof 20 of the dryer for operationof the drying chamber air control dampers 120, 122, 124, 126, ashereinafter more fully set forth. A pair of fan motors 22, 24, affix toframe roof structural members 26, 28, 30, 32, above the roof 20 inwell-known manner, and rotate the fan shafts 34, 36, to operate the fans38, 40, as hereinafter more fully set forth. The shafts 34, 36,respectively journal through the dryer roof construction 20 in wellknown manner, to provide sturdy, vibration free fan operation to directheated air through the interior of the apparatus.

The interior of the dryer 10 is subdivided into a plurality ofconnecting chambers, by utilizing a plurality of horizontal and verticalbaffles and dampers which position within the bafflesto preciselyregulate volume, direction, and temperature of the heated air as ittravels within the dryer unit. As best seen in FIGS. 2 and 3, the heatedair fan 38 pushes the heated air horizontally through the initialchamber 42 towards the forward vertical chamber 44 in the directionindicated by the arrow 46. The curved baffle 48 directs the flow ofheated air from the horizontal direction in the initial chamber 42 to avertical direction in the forward chamber 44 in a smooth transition andvibration-free manner. The drying chamber 50 receives the heated aireither downwardly as indicated by the arrow 52 in FIG. 2, or upwardly asindicated by the arrow 54 in FIG. 3, in the manner hereinafter morefully explained. The heated air exits the drying chamber 50 through theafter chamber 56 where it may be directed through the exit chamber 58 asindicated by the arrow 60, or else all, or a portion, of the air isguided through the combustion chamber 62 as indicated by the arrow 64 inthe manner hereinafter more fully set forth. The heater chamber 66positions rearwardly of the combustion chamber 62 and receivescombustion air either through the side wall opening 68 (FIG. 1), or fromthe exhaust gas stream as indicated by the arrow 70. (See FIGS. 2 and3).

As best seen in FIGS. 2 and 3,'a horizontal baffle 72 defines the floorof the initial chamber 42 which directs heated air forwardly through thedryer 10. A pivoted damper 74 journals through upright members of theframe 12 and opens as indicated in phantom lines in the direction of theflow ofheated air to provide a recirculation path through therecirculating chamber 76 as indicated by the arrow 78. Recirculation maybe indicated when it is desired to increase temperatures. A gear motorcontrol 16 mounts upon the roof 20 and pivots the damper 74 about itspivot through the external linkage 80 in response to additional controls(not shown). The damper 74 serves to closely regulate the volume of airrecirculated through the recirculation chamber 76 and the volume of airintroduced to the drying chamber 50 through the forward vertical chamber44.

The drying chamber 50 is defined between the recirculation chamberbaffle 82 which serves as the roof, the forward vertical chamber baffle84 which serves as the forward wall and the after chamber baffle 86which forms the rear wall thereof. A pair of intermediate, transversesheet steel arms 88, 90, medially depend respectively from the baffles84, 86, and form substantially air-tight, upper, transverse junctions92, 94, therewith. The depending sheet steel sections 96, 98, terminatedownwardly in co-operating, facing ledges 100, 102, which space apart asufficient distance to carry the tray 104 to support the articles 106being dried medially within the drying chamber 50. Each dependingsection 96, 98, forces inwardly at the respective ledges 100, 102, underurging of the compression springs 108, 110, which bias between a fixedportion of the frame 12 and the baffle side of the depending sections96, 98. The springs 108, 110, continuously urge the arms 88, 90, intosubstantially air-tight, transverse contact with the forward andrearward edges of the tray 104 at the respective bottom ledges 100, 102,to assure complete heated air impingement upon the articles 106, eitherdownwardly through the tray as in FIG. 2, or upwardly through the trayas in FIG. 3.

The vertical chamber baffle 84 and the after chamber baffle 86 eachtransversely divide to form the upper air passage openings 112, 114,andthe lower'air passage openingsll6, 118,'to facilitate airmovementboth upwardly and downwardly through the drying chamber 50 in thedirections illustrated'by the arrows 52,54, in FIGS. 2 and 3. Each airpassage opening 112, 114, 116, 118, is equipped with a respective,pivoting damper blade 120, 122, 124, 126, for opening or closing theassociated air passage in response to operation of the gear motorcontrol operator 18 as desired by the operator of the equipment.

Referring now, to FIG. 1, the gear motor control operator 18 functionsthe external vertical linkage 128, and the connecting, externalhorizontal linkage 130,

132, which pin together in a manner to assure simultaneous operation.Asillustrated, the horizontal linkage 130 functions the damper. blades120, 122, and connects to the vertical linkage 128, in a manner to openthe damper blade 120when damper blade.122 closes, and vice versa.Similarly, the horizontal linkage 132 connects to the verticallinkage128, to operate the lower'dampers124, 126, simultaneously in a manner toopen the damper 124 when damper 126 closes, and vice versa. Also, asbest seen in FIGS. 2 and 3, the upper damper 120 opens when the lowerdamper 124 closes, and the upper damper 122 closes when the lower damper126 opens. All four dampers 120, 122, 124, 126, function in unison uponoperation of the gear motor control operator 18 from an initial positionas in FIG. 2 to a final position as in FIG. 3. e

When the operator 18 rotates its operating arm 19 to its initialposition, the dampers 120, 126, open and the dampers 1-24, 122, close todirect the heated air downwardly through the drying chamber in thedirection indicated by the arrow 52. See FIG. 2. When the operator 18rotates its operating arm 19 to its final position, the dampers 120,126, close and the dampers 124, 122, open to direct heated air from'theforward vertical chamber 44 upwardly through the tray 104 in thedirection indicated by the arrow 54. See FIG. 3. Thus, by simplefunction of the operator 18 from a first position to a second position,either a downward flow path through the drying chamber 50 results asillustrated in FIG. 2, or an upward flow path through the drying chamber50 may be provided as illustrated in FIG. 3.

The gear motor control operator 134 affixes to a stationary portion ofthe frame and pivots the second recirculation damper 136 from an openposition as illustrated in FIGS. 2 and 3, toward a closed, horizontalposition, (not shown), by utilizing the internal connecting linkage 138in the usual manner. The recirculation damper 136, when in a closedposition, closes upon the solid stop. 140 to thereby direct all air fromthe after chamber 56 towards the exit chamber 58 along the pathindicated by the arrow 142. In this manner, humid air from the dryingchamber 50 may be completely exthrough the combustion chamber 62 alongthe path of the arrow 64. More or less recirculated air may be directedinto the combustion chamber 62 by regulating the opening position of thechamber 136 to thereby precisely control humidity conditions in thedrying chamber.

' The air heater 144, of any well known design, pulls its combustionairthrough the opening 68 and directs its flame 146 into the combustionchamber 62 wherein the heated air flows to-the suction of the fan 38. A

, secondary air damper 148 journals within the frame 12 and pivots froman open position as illustrated in FIGS. 2 and 3, to a closed positionto optionally admit or bar the entrance of heated air into the heaterchamber 66 along the path indicated by the arrow 70. A gear motorcontrol operator 150 functions the damper 148 through the internallinkage 152 in response to external controls (not shown), thereby toprovide convenient, economical utilization. of the waste heat wheneverso desired. It will be appreciated that the exit gases traveling alongthe path 142 have already been pre-heated in the combustion chamber 62and, accordingly, any heated air reintroduced into the heater chamber 66about the damper 148 will require less fuel to reheat to operatingtemperatures.

The exhaustfan 40 positions near the dryer roof 20 with its suction atthe top of the exit chamber 58, and cooperates to pull the heated airthrough the dryer 10 in conjunction with the pressurizing effect of thefan 38. The exhaust air exits the dryer 10 at the fan 40 discharge, asillustrated by the arrow 154.

In operation, the air heater 144 heats the drying air in the combustionchamber 62 where it then travels upwardly toward the suction of theheated air fan 38. The heated air travels through the horizontal,initial chamber 42 under impetus of the fan 38 and downwardly into theforward vertical chamber 44. If it is desired to reduce the volume ofair introduced into the combustion chamber as determined by the dryingrequirements of the articles 106, the operator 16 is energized tofunction the vertical linkage 80 to open the damper 74 for recirculationof a pre-determined volume of air along the path of the arrow 78. airfollows the path 46 through the forward vertical chamber 44 and entersthe drying chamber 50, either above the tray 104 along the path 52 as inFIG. 2, or from below the hausted. When it is desired to recirculate theair from tray 104 along the path 54, as in FIG. 3. The path through thedrying chamber 50 may be readily controlled by functioning the operator18 from an initial position as in FIG. 2 to a final position as in FIG.3, thereby to simultaneously pivot the respective damper blades 120,122, 1 24, 126, to provide either desired flow path. After exiting thedrying chamber 50 through either the opening 114 or the opening 118, allof the exhaust air may be discharged through the exit chamber 58 by theexhaust fan 40. Optionally, a portion of the exhaust air may berecirculated along the path 64 upon opening the damper 136 by operationof the linkage 138 through the operator 134. External controls, (notshown), function the operator 134, thereby to allow heated exhaust aireither to recirculate upwardly through the combustion chamber 62 or toexit the dryer 10 along the path of the arrows 142, 60, 154.

Combustion air for the air heater 144 enters the heater chamber 66through the opening 68. If desired,

velocity, and volume, may be incorporated in well known manner tomonitor dryer environmental conditions and to automatically function thevarious operators l6, 18, 134, 150, to vary the interior conditions.

What I claim is:

l. in an article dryer of the type including an enclosing casing, an airheater operatively positioned within the casing and fan means directinga heated air stream through a drying chamber, the combination consistingof:

A. a frame supporting the said casing,

B. baffle means interiorly affixed to portions of the said frame,

l. said baffle means subdividing the interior of the dryer into aplurality of chambers,

2. a first portion of said baffle means defining an article dryingchamber,

said first portion of the bafile means including a forward dryingchamber baffle and a rearward drying chamber baffle, each of said dryingchamber baffles being provided with respective upper and lower openings;

C. first damper means positioned in the first portion of the bafflemeans and journalled into the frame for rotative movement with respectthereto,

1. said first damper means having a first position and a secondposition,

2. said first damper means directing heated air upwardly through thedrying chamber when in the said first position,

3. said first damper means directing heated air downwardly through thedrying chamber when in the said second position,

4. said first damper means rotating within the said upper and loweropenings,

:1. said first damper means including upper and lower forward dampers,and upper and lower rearward dampers,

b. the said upper forward damper closing the forward baffle upperopening, and the lower forward damper opening the forward baffle loweropening when the first damper means assumes the said first position.

2. The invention of claim 1 wherein the upper rearward damper opens therearward baffle upper opening, and the lower rearward damper closes therearward baffle lower opening when the first damper means assumes thesaid first position.

3. The invention of claim 1 wherein a second portion of the said bafflemeans defines a combustion chamber, said combustion chamber beingpositioned downstream of the drying chamber, said combustion chamberbeing equipped with a recirculation damper which is movable between anopen os ition and a closed position, said second recircu atlon damperdirecting a portion of the heated air stream effluent from the dryingchamber into the combustion chamber when in the said open position.

4. The invention of claim 3 wherein a third portion of said bafile meansdefines a heater chamber, said heater chamber being positioneddownstream of the drying chamber, said heater chamber being equippedwith a damper which is movable between an open position and a closedposition, said damper directing a portion of the heated air streameffluent from the drying chamber into the heater chamber when in thesaid open position.

5. In an article dryer of the type including an enclosing casing, an airheater operatively positioned within the casing, and fan means directinga heated air stream through a drying chamber, the combination consistingof:

a. a frame supporting the said casing,

b. baffle means interiorly affixed to portions of the said frame,

said baffle means subdividing the interior of the said dryer into aplurality of chambers,

a first portion of said baffle means defining an article drying chamber,

c. first damper means positioned in the first portion of the bafflemeans and journalled into the frame for rotative movement with respectthereto, said first damper means having a first position and a secondposition, said first damper means directing heated air upwardly throughthe drying chamber when in the said first position, said first dampermeans directing heated air downwardly through the drying chamber when inthe said second position,

d. second damper means positioned upstream from the first damper means,said second damper means recycling a portion of the heated air to thefan means, and

e. third damper means positioned within the casing downstream from thedrying chamber, said third damper means recycling a portion of theheated air efiluent from the drying chamber to the said fan means.

1. In an article dryer of the type including an enclosing casing, an airheater operatively positioned within the casing and fan means directinga heated air stream through a drying chamber, the combination consistingof: A. a frame supporting the said casing, B. baffle means interiorlyaffixed to portions of the said frame,
 1. said baffle means subdividingthe interior of the dryer into a plurality of chambers,
 2. a firstportion of said baffle means defining an article drying chamber, saidfirst portion of the baffle means including a forward drying chamberbaffle and a rearward drying chamber baffle, each of said drying chamberbaffles being provided with respective upper and lower openings; C.first damper means positioned in the first portion of the baffle meansand journalled into the frame for rotative movement with respectthereto,
 1. said first damper means having a first position and a secondposition,
 2. said first damper means directing heated air upwardlythrough the drying chamber when in the said first position,
 3. saidfirst damper means directing heated air downwardly through the dryingchamber when in the said second position,
 4. said first damper meansrotating within the said upper and lower openings, a. said first dampermeans including upper and lower forward dampers, and upper and lowerrearward dampers, b. the said upper forward damper closing the forwardbaffle upper opening, and the lower forward damper opening the forwardbaffle lower opening when the first damper means assumes the said firstposition.
 2. a first portion of said baffle means defining an articledrying chamber, said first portion of the baffle means including aforward drying chamber baffle and a rearward drying chamber baffle, eachof said drying chamber baffles being provided with respective upper andlower openings; C. first damper means positioned in the first portion ofthe baffle means and journalled into the frame for rotative movementwith respect thereto,
 2. said first damper means directing heated airupwardly through the drying chamber when in the said first position, 2.The invention of claim 1 wherein the upper rearward damper opens therearward baffle upper opening, and the lower rearward damper closes therearward baffle lower opening when the first damper means assumes thesaid first position.
 3. The invention of claim 1 wherein a secondportion of the said baffle means defines a combustion chamber, saidcombustion chamber being positioned downstream of the drying chamber,said combustion chamber being equipped with a recirculation damper whichis movable between an open position and a closed position, said secondrecirculation damper directing a portion of the heated air streameffluent from the drying chamber into the combustion chamber when in thesaid opEn position.
 3. said first damper means directing heated airdownwardly through the drying chamber when in the said second position,4. said first damper means rotating within the said upper and loweropenings, a. said first damper means including upper and lower forwarddampers, and upper and lower rearward dampers, b. the said upper forwarddamper closing the forward baffle upper opening, and the lower forwarddamper opening the forward baffle lower opening when the first dampermeans assumes the said first position.
 4. The invention of claim 3wherein a third portion of said baffle means defines a heater chamber,said heater chamber being positioned downstream of the drying chamber,said heater chamber being equipped with a damper which is movablebetween an open position and a closed position, said damper directing aportion of the heated air stream effluent from the drying chamber intothe heater chamber when in the said open position.
 5. In an articledryer of the type including an enclosing casing, an air heateroperatively positioned within the casing, and fan means directing aheated air stream through a drying chamber, the combination consistingof: a. a frame supporting the said casing, b. baffle means interiorlyaffixed to portions of the said frame, said baffle means subdividing theinterior of the said dryer into a plurality of chambers, a first portionof said baffle means defining an article drying chamber, c. first dampermeans positioned in the first portion of the baffle means and journalledinto the frame for rotative movement with respect thereto, said firstdamper means having a first position and a second position, said firstdamper means directing heated air upwardly through the drying chamberwhen in the said first position, said first damper means directingheated air downwardly through the drying chamber when in the said secondposition, d. second damper means positioned upstream from the firstdamper means, said second damper means recycling a portion of the heatedair to the fan means, and e. third damper means positioned within thecasing downstream from the drying chamber, said third damper meansrecycling a portion of the heated air effluent from the drying chamberto the said fan means.